The instant invention is in the same general field as that of my prior U.S. Pat. No. 3,689,236 issued Sept. 5, 1972 and constitutes an improvement thereover. The device of said prior patent employed an air valve having external parts subject to excessive deterioration and damage, and employed a fuel control valve downstream of the air valve. Also, the prior device constituted a carburetor usable with either liquid or gaseous fuel.